Delicate Blue-eye - Pseudomugil tenellus

The Delicate Blue-eye was scientifically described by Taylor in 1964. Its scientific name is Pseudomugil tenellus. It was first collected for scientific purposes in 1964 by an American ichthyologist named Miller.

Description
The Delicate Blue-eye can reach a length of 5.5 cm (2.2 inches). The body is semi-translucent or light blue-grey and the upper half is adorned with fine, dark scale outlines that form a decorative network. The fish is also embellished with roughly a dozen of pearly dots that form a mid-lateral row along the side of the body. The fins are usually yellowish.

Geographical distribution, habitat and conservation
The Delicate Blue-eye can be found in both northern Australia and southern New Guinea. In Australia, it can be found between Darwin and Blyth River in the Northern Territory and in the Edward River on the Cape York Peninsula of Queensland.

In New Guinea, Delicate Blue-eye has only been found in the Bensbach River. The Bensbach River is the westernmost river in Papua New Guinea and its runs through lowland forest and grassland until it empties itself into the ocean at the border to West Papua.

The Delicate Blue-eye lives in swampy environments and slow backwaters, including billabongs (a type of marshy pond) and overflow pools created by rivers and creeks. The bottom will normally consist of gravel, sand or mud. During the dry season, you can find Delicate Blue-eyes in stagnant pools and puddles.

The Delicate Blue-eye is usually found in non-shadowed waters with rich vegetation both above and under water. In some habitats, the water is turbid due to do suspended algae. The water temperature within the species geographical range is 25-35 degrees C (77-95 degrees F).

The Delicate Blue-eye is listed as “Not Evaluated” on the IUCN Red List of Threatened Species.

Keeping Delicate Blue-eye in aquariums
The species is not a commonly kept blue-eye, especially not outside Australia. The Delicate Blue-eye must be carefully nursed back to health after being transported, but if you manage to make your fish recover it will turn in to quite an easy species to care for in the aquarium. Since the fish is so small, even a 20 litre (5 gallon) aquarium is large enough to house a small group of Delicate Blue-eyes. You should however keep in mind that it can be hard to keep the water quality up in such a small aquarium. You have to be prepared to carry out really frequent water changes. The Delicate Blue-eye is often kept in species aquariums, but it can also be combined with non-aggressive species of a similar size in a community set up.

Try to resemble the natural habitat of the Delicate Blue-eye and use driftwood and plenty of aquatic plants to create hiding spots in the aquarium. Strong water current is not recommended, since the Delicate Blue-eye is used to backwaters, slow-flowing creeks and stagnant pools.

The recommended water temperature for Delicate Blue-eyes is 25-30 degrees C (77-86 degrees F). Keep the water acidic or just slightly alkaline, from pH 6.0 to 7.2.

Breeding Delicate Blue-eye
The Delicate Blue-eye reaches sexual maturity when it is roughly 2.5 cm (1 inch) long and this may occur when the fish is no older than three months old if kept on a nutritious diet. This species can be bred in both groups and pairs and is known to readily spawn in aquariums.

If you want your Delicate Blue-eyes to breed, it is advisable to include floating plants or floating mops in the aquarium set up and keep your fish on a varied and nutritious diet. If additional coaxing turns out to be necessary, try moving the aquarium to spot where it receives roughly one hour of natural sunlight each morning.

During spawning, the female will deposit her sticky eggs among the floating plants/mops. The safest course of action is to move the spawning medium with the eggs to a separate container in order to avoid predation.

If you keep the water temperature in the upper part of the recommended range, Delicate Blue-eye eggs will normally hatch within 5 days. You can feed the fry infusoria and finely ground flake food until they are big enough to eat newly hatched brine shrimp and whole flake food.